Energy storage battery system and operation control method thereof

Abstract

The invention provides an energy storage battery system and an operation control method thereof, and relates to the field of energy storage control. The energy storage battery system comprises a plurality of battery packs, wherein each battery pack comprises a plurality of battery cells which are connected in parallel; the plurality of battery pack energy optimizers PEO are arranged in one-to-one correspondence with the plurality of battery packs; the power converter PCS is electrically connected with an external electrical circuit and is configured to control the energy storage battery system to perform electric energy interaction with the electrical circuit; the power distribution unit PDU is respectively connected with the power converter and the plurality of battery pack energy optimizers, and is configured to convert a conversion instruction of the power converter into a plurality of battery pack optimization instructions and distribute the plurality of battery pack optimization instructions to the plurality of battery pack energy optimizers; and the plurality of battery pack energy optimizers carry out charging and discharging operation according to the respective battery pack optimization instructions. According to the scheme, the electric energy conversion and utilization efficiency is improved, and the energy loss is reduced.

Description

Technical Field

[0001] This invention relates to the field of energy storage control, and in particular to an energy storage battery system and its operation control method. Background Technology

[0002] Battery energy storage systems (BESS) are systems that store electrical energy in the form of chemical energy and release it when needed. Their core components include batteries and power conversion systems (PCS).

[0003] The batteries are connected in series and parallel to increase their own voltage and energy storage capacity, ensuring that their output voltage matches the DC voltage range of the power conversion system. This allows them to connect to the power grid for charging and discharging. The power conversion system converts AC to DC energy from the grid using power electronics, storing it in the battery system; the discharging process is the reverse.

[0004] During the charging and discharging process, due to its electrochemical characteristics, the voltage of a battery will fluctuate, and its internal resistance will increase as the amount of charge is lost. During the charging and discharging process, the power conversion system will experience fluctuations in conversion efficiency within a certain range due to different input voltage values ​​and different charging and discharging states.

[0005] A battery cell is the basic unit of a battery. Common battery types include lithium-ion batteries (such as lithium iron phosphate (LFP) and ternary NMC), while other types include lead-acid batteries, sodium-sulfur batteries, and flow batteries. Multiple cells are connected in series and parallel to form a battery pack (or battery module). During long-term operation, cells gradually develop performance differences, leading to charging and discharging imbalances. This imbalance further causes significant deviations in the overall performance of the battery pack, ultimately resulting in a loss of capacity and energy, shortening its lifespan, and increasing safety risks.

[0006] Existing energy storage battery systems typically rely on voltage and temperature to detect battery operational problems, and then perform cell equalization operations to resolve them. However, these equalization operations unnecessarily consume a significant amount of electrical energy, resulting in low efficiency. Summary of the Invention

[0007] One object of the present invention is to provide an energy storage battery system that reduces losses and improves operating efficiency.

[0008] A further objective of this invention is to prevent damage to the battery cells caused by charging and discharging the energy storage battery beyond its operating limits.

[0009] Another further object of the present invention is to facilitate timely maintenance and repair of potential faults.

[0010] According to one aspect of the present invention, an energy storage battery system is provided, comprising:

[0011] Multiple battery packs, each battery pack comprising multiple cells connected in parallel;

[0012] Multiple battery pack energy optimizers (PEOs) are configured to correspond one-to-one with each battery pack.

[0013] The power converter PCS is electrically connected to the external electrical circuit and configured to control the energy storage battery system to interact with the electrical circuit.

[0014] The power distribution unit (PDU) is connected to the power converter and multiple battery pack energy optimizers, and is configured to convert the conversion instructions of the power converter into multiple battery pack optimization instructions, and distribute the multiple battery pack optimization instructions to the multiple battery pack energy optimizers so that the multiple battery pack energy optimizers can perform charging and discharging operations according to their respective battery pack optimization instructions.

[0015] Optionally, the power distribution unit (PDU) is further configured to: obtain the optimal efficiency point of the power converter (PCS), determine the operating voltage value of each battery pack energy optimizer (PEO) and the battery pack power index based on the optimal efficiency point, and generate battery pack optimization instructions based on the operating voltage value and the battery pack power index.

[0016] Optionally, the above-mentioned energy storage battery system further includes:

[0017] Multiple cell energy optimizer CEOs are configured, each corresponding to a specific cell, and

[0018] Each battery pack energy optimizer (PEO) is also connected to the plurality of cell energy optimizers (CEOs) of its corresponding battery pack, and configured to convert battery pack optimization instructions into multiple cell optimization instructions, and distribute the multiple cell optimization instructions to the multiple cell energy optimizers (CEOs) so that the multiple cell energy optimizers (CEOs) can perform charging and discharging operations according to their respective cell optimization instructions.

[0019] Optionally, each battery pack energy optimizer (PEO) is further configured to lock the operating voltage of the battery pack according to the operating voltage value in the battery pack optimization instruction, and to generate cell optimization instructions for each cell energy optimizer (CEO) according to the battery pack power index in the battery pack optimization instruction.

[0020] Optionally, the cell energy optimizer CEO is also configured to track the operating voltage of the corresponding battery pack energy optimizer PEO and adjust the charging and discharging current of the corresponding cell according to the cell optimization instructions.

[0021] Optionally, the power converter PCS is also configured to collect the overall status data of the energy storage battery system after receiving the charge / discharge command during the standby phase of the energy storage battery system; and send the battery pack self-test command to multiple battery pack energy optimizers PEO through the power distribution unit PDU, and obtain the battery pack status data replied by the multiple battery pack energy optimizers PEO in response to the battery pack self-test command.

[0022] The battery pack energy optimizer (PEO) is also configured to collect corresponding battery pack status data according to the battery pack self-test command, send cell self-test commands to multiple cell energy optimizers (CEOs) according to the battery pack self-test command, and obtain cell status data replied by multiple cell energy optimizers (CEOs) in response to the cell self-test command.

[0023] Optionally, the battery pack energy optimizer (PEO) is also configured to update the battery pack status data based on the cell status data;

[0024] The power converter PCS is also configured to update the overall status data of the energy storage battery system based on the battery pack status data.

[0025] Optionally, the battery pack energy optimizer (PEO) is also configured to determine whether the battery pack power index exceeds the allowable range of the updated battery pack status data. If not, the battery pack optimization command is converted into multiple cell optimization commands based on the cell status data. If so, the information that the battery pack power index exceeds the limit is fed back through the power distribution unit (PDU).

[0026] Optionally, the power converter PCS is also configured to perform a system self-test based on the updated overall status data of the energy storage battery system. If the self-test passes, a conversion command is generated based on the overall status data of the energy storage battery system; if the self-test fails, an alarm message indicating an abnormality in the battery system is output.

[0027] According to another aspect of the present invention, an operation control method for an energy storage battery system is also provided, for controlling any of the above-described energy storage battery systems, and comprising:

[0028] Find the optimal efficiency point of the power converter PCS;

[0029] The operating voltage value of the energy optimizer (PEO) for each battery pack and the power specifications of the battery pack are determined based on the optimal efficiency point.

[0030] Generate battery pack optimization instructions based on operating voltage values ​​and battery pack power specifications;

[0031] The battery pack optimization instructions are distributed to multiple battery pack energy optimizers, so that the multiple battery pack energy optimizers perform charging and discharging operations according to their respective battery pack optimization instructions.

[0032] Optionally, prior to the step of obtaining the optimal efficiency point of the power converter PCS, this method further includes:

[0033] After receiving a charge / discharge command during the standby phase of the energy storage battery system, the overall status data of the energy storage battery system is collected.

[0034] The power distribution unit (PDU) sends a battery pack self-test command to the battery pack energy optimizer (PEO).

[0035] Obtain battery pack status data in response to the battery pack self-test command from the battery pack energy optimizer (PEO).

[0036] Update the overall status data of the energy storage battery system based on the battery pack status data;

[0037] The system performs a self-test based on the updated overall status data of the energy storage battery system. If the self-test passes, the system proceeds to obtain the optimal efficiency point of the power converter. If the self-test fails, an alarm message indicating an abnormality in the battery system is output.

[0038] The energy storage battery system and its control operation method of the present invention obtain the optimal efficiency point of the power converter PCS through the power distribution unit (PDU), and determine the operating voltage value of the battery pack energy optimizer (PEO) and the battery pack power index accordingly, so that the entire energy storage battery system can operate at a state close to the optimal efficiency of the power converter, thereby improving the efficiency of power conversion and utilization and reducing energy loss.

[0039] Furthermore, the energy storage battery system and its control operation method of the present invention achieve refined charge and discharge control, with the system performing hierarchical optimization control from the battery pack level to the cell level. The battery pack energy optimizer PEO converts battery pack optimization commands into cell optimization commands, and the cell energy optimizer CEO adjusts the cell charge and discharge current according to the commands. This refined control helps to extend battery life and avoid damage to the cells caused by overcharging or uneven charging and discharging.

[0040] Furthermore, the energy storage battery system and its control operation method of the present invention, upon receiving a charge / discharge command during the standby phase, are capable of acquiring overall status data and performing self-checks on the battery pack and cells. Through layer-by-layer data acquisition and updating, the power converter PCS can perform system self-checks based on the updated overall status data, promptly detect system anomalies and issue alarms, thereby improving the reliability and stability of system operation and facilitating timely maintenance and repair of potential faults.

[0041] Furthermore, in the energy storage battery system and control operation method of the present invention, the power distribution unit (PDU) can convert the instructions of the power converter into battery pack optimization instructions, and the battery pack energy optimizer (PEO) can adjust the instructions or provide feedback on power index over-limit information based on the cell status data. This flexible instruction conversion and feedback mechanism enables the system to dynamically adjust according to the actual battery status, ensuring the safe and stable operation of the system.

[0042] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0043] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0044] Figure 1 This is a schematic diagram of the electrical connections of an energy storage battery system according to an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of an operation control method for an energy storage battery system according to an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram of the execution flow of the power distribution unit during the operation of an energy storage battery system according to an embodiment of the present invention. Detailed Implementation

[0047] Those skilled in the art should understand that the embodiments described below are merely a part of the embodiments of the present invention, and not all of the embodiments of the present invention. These partial embodiments are intended to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those skilled in the art without creative effort should still fall within the scope of protection of the present invention.

[0048] Figure 1This is a schematic diagram of the electrical connections of an energy storage battery system according to an embodiment of the present invention. The energy storage battery system generally includes: multiple battery packs 130, multiple battery pack energy optimizers (PEOs) 131, a power converter (PCS) 110, and a power distribution unit (PDU) 120. In some implementation scenarios with more refined control, multiple cell energy optimizers (CEOs) 132 may also be included. These components cooperate to achieve efficient and stable operation of the energy storage battery system.

[0049] Each battery pack 130 consists of multiple cells 133 connected in parallel. This parallel connection architecture can meet the energy storage capacity requirements of different application scenarios. This connection method not only improves the power supply capacity of the battery system but also enhances the system's reliability to a certain extent, because when one cell fails, the other cells can still provide power to maintain the basic operation of the system.

[0050] The energy storage battery system connects multiple battery packs 130 in series and parallel, which can increase the input and output voltage of the energy storage battery system as needed. In typical applications, the voltage formed by multiple battery packs 130 connected in series can reach hundreds of volts or even higher. For example, in residential energy storage scenarios, 15 or 16 energy storage battery packs can be connected in series to form a battery cluster, and the voltage of the resulting battery cluster can reach approximately 800V. The specific voltage level and series / parallel connection method can be configured according to requirements.

[0051] The power converter PCS110 is electrically connected to external electrical circuits and configured to control the energy storage battery system's interaction with these circuits. The main component of the PCS110 is an inverter, used to convert the battery pack's electrical energy into alternating current (AC) for direct power supply to the load or for transmission to the grid. The PCS110 has DC and AC terminals; the DC terminal connects to the battery pack, and the AC terminal connects to the load or the AC grid. The PCS110 performs AC / DC conversion based on the load, grid requirements, and the state of the energy storage battery system. When the energy storage battery system needs to supply power to an external load, the PCS110 converts the DC output from the battery pack 130 into AC power suitable for the external electrical circuits, meeting the needs of various AC devices. Conversely, when the energy storage battery system needs charging, the PCS110 converts the AC input from the external electrical circuits into DC power to replenish the battery pack. Furthermore, when the energy storage battery system is in standby mode and receives a charge / discharge command, the power converter PCS110 quickly initiates a series of operations. First, it collects overall status data of the energy storage battery system, including key information such as the total voltage, total current, remaining capacity, and battery temperature. Subsequently, the power converter PCS110 sends battery pack self-test commands to multiple battery pack energy optimizers PEO131 via the power distribution unit PDU120, and receives battery pack status data from the PEO131 in response to these commands, thus gaining a comprehensive understanding of the battery system's health status.

[0052] The optimal efficiency point of the PCS110 power conversion system refers to the operating state in which the PCS achieves the highest power conversion efficiency under a certain operating condition. This state is usually determined by parameters such as input / output voltage, current, and temperature, and its core objective is to minimize losses during the energy conversion process.

[0053] The power distribution unit (PDU120) is connected to the power converter (PCS110) and multiple battery pack energy optimizers (PEO131). It plays a crucial role in the entire system, determining the optimal efficiency point of the PCS110. This optimal efficiency point is vital for the efficient operation of the entire energy storage battery system, serving as a key basis for system parameter adjustments. Based on this optimal efficiency point, the PDU120 performs precise calculations and analysis to determine the operating voltage and power specifications of each battery pack energy optimizer (PEO131), generating targeted battery pack optimization instructions and accurately distributing these instructions to the multiple PEO131s. For example, under different power consumption scenarios and battery states, the PDU120 dynamically adjusts the operating parameters of each battery pack (PEO130) based on the optimal efficiency point of the PCS110, ensuring that the entire energy storage battery system always operates close to the optimal efficiency of the PCS110, thereby maximizing energy utilization efficiency and minimizing energy consumption. The power distribution unit PDU120 can determine the optimal efficiency point based on the power conversion requirements of the power converter PCS110, combined with voltage, device, and environmental data, and an efficiency model (such as a pre-established curve showing the relationship between efficiency and relevant parameters).

[0054] Multiple battery pack energy optimizers (PEO131) are configured one-to-one with multiple battery packs 130, meaning that each battery pack 130 is equipped with one battery pack energy optimizer (PEO131). The battery pack energy optimizer (PEO131) is used to receive battery pack optimization commands from the power distribution unit (PDU120) and to perform precise charging and discharging operation control on the corresponding battery pack 130 according to these commands.

[0055] In embodiments equipped with a cell energy optimizer CEO132, the battery pack energy optimizer PEO131 is further used to convert the battery pack optimization instructions into cell optimization instructions and distribute them to the corresponding multiple cell energy optimizers CEO132. This allows for the rational allocation of the charging and discharging process of the battery pack 130 based on the overall system operating requirements and the real-time status of the battery pack, ensuring that the battery pack 130 is always in its optimal operating state.

[0056] Multiple cell energy optimizers (CEO132) are configured in a one-to-one correspondence with each cell 133, meaning each cell 133 is equipped with one CEO132. The battery pack energy optimizer (PEO131) converts the battery pack optimization instructions into multiple cell optimization instructions and then transmits them to the corresponding CEO132 cells. Each CEO132 cell performs charging and discharging operations according to its respective cell optimization instructions. Each CEO132 cell closely tracks the operating voltage of its corresponding PEO131 cell and finely adjusts the charging and discharging current of the corresponding cell based on the cell optimization instructions. This refined, hierarchical control strategy from the battery pack 130 to the cells 133 effectively solves the performance degradation problem caused by inconsistent charging and discharging between the battery pack 130 and the cells 133. For example, during charging, the CEO132 cell controls the charging of the cells according to the charging power allocated by the PEO131 cell and monitors the cell voltage in real time to optimize cell charging. During the discharge process, the cell energy optimizer CEO132 controls the cell discharge according to the cell discharge power allocated by the battery pack energy optimizer PEO131, and performs cell discharge optimization.

[0057] The CEO132 cell energy optimizer can also detect the charging and discharging process of cell 133 and adjust the charging and discharging current of cell 133 in a timely manner to avoid overcharging and discharging, thereby significantly extending the service life of the entire battery system and improving the overall performance and reliability of the battery system.

[0058] When in standby mode, the energy storage battery system can be configured to respond to charging and discharging operations at any time. That is, after the energy storage battery system is in standby mode and receives a charging / discharging command, the power converter PCS110 executes a system self-test process. The power converter PCS110 first comprehensively collects overall status data of the energy storage battery system; this data is crucial for assessing the system's current operating condition. Subsequently, the power converter PCS110 sends a battery pack self-test command to the battery pack energy optimizer PEO131 via the power distribution unit PDU120. The overall status data of the energy storage battery system may include: total system voltage, remaining system charge (SOC), system internal resistance, system ambient temperature, total cycle count, device connection status, fault alarm information, etc.

[0059] The output or input voltage of the entire energy storage battery system is used to determine whether the battery system is within its normal operating voltage range. Excessively high or low voltage may indicate abnormal battery pack connection (133), individual battery failure, or problems with the charging / discharging equipment. State of Charge (SOC) reflects the proportion of usable battery capacity remaining. Accurate SOC estimation is crucial for determining the battery's charge / discharge schedule. The battery's internal resistance affects its charging / discharging efficiency and performance. Internal resistance gradually increases with battery use and aging. Measuring total internal resistance can indirectly assess the battery's health. Excessively high or low ambient temperatures can affect battery operation; combined with the heat generated during charging and discharging, this can lead to thermal runaway and even safety accidents. Cycle count records the number of complete charge / discharge cycles the battery has completed, and it is important for estimating battery lifespan. The device connection status reflects whether the connections between the power converter PCS110 and external electrical lines, the battery pack 130 and power distribution unit PDU120, the battery pack energy optimizer PEO131 and cell energy optimizer CEO132, and the cell energy optimizer CEO132 and cell 133 are normal. Fault alarm information consists of fault information reported by each component, used for fault location.

[0060] Upon receiving the instruction, the battery pack energy optimizer PEO131 collects detailed status data for the corresponding battery pack 130, including parameters such as voltage, temperature, and internal resistance of each cell 133 within the battery pack 130. Simultaneously, it sends cell self-test instructions to multiple cell energy optimizers CEO133. Upon receiving the instructions, the cell energy optimizers CEO133 accurately collect the status data of the corresponding cells and promptly feed this data back to the battery pack energy optimizer PEO131. The battery pack energy optimizer PEO131 comprehensively updates the battery pack status data based on the cell status data, ensuring the accuracy and completeness of the data, and then feeds the updated battery pack status data back to the power converter PCS110. The power converter PCS110 updates the overall status data of the energy storage battery system again based on the battery pack status data and performs a system self-test using a preset self-test algorithm based on the updated overall status data.

[0061] If the self-test results show that all system indicators are normal, the power converter PCS110 generates conversion instructions based on the overall status data of the energy storage battery system, preparing for subsequent charging and discharging operations. If an abnormality is found in the system during the self-test, the power converter PCS110 will immediately output an alarm message for the battery system abnormality, promptly reminding the operator to check and repair the system to avoid potential safety hazards and performance loss.

[0062] After completing and confirming the system self-test, the Power Distribution Unit (PDU120) begins to acquire the optimal efficiency point of the power converter. Based on this optimal efficiency point, the PDU120 uses a complex and precise calculation model to determine the operating voltage value and power specifications of each battery pack energy optimizer (PEO131), thereby generating detailed battery pack optimization instructions and accurately distributing these instructions to multiple PEO131 battery pack energy optimizers. The PDU120 executes overall adjustments to the energy storage battery system through the BMS (Battery Management System) and acquires relevant data about the entire energy storage battery system from the BMS.

[0063] Upon receiving a battery pack optimization command, the battery pack energy optimizer PEO131 locks the operating voltage of the battery pack 130 according to the operating voltage value in the command, ensuring that the battery pack 130 operates under stable voltage conditions. Simultaneously, based on the battery pack power specifications and the real-time status of the cells 133, it generates cell optimization commands for each cell's energy optimizer. For example, if the battery pack optimization command requires the battery pack 130 to charge at a specific power, the battery pack energy optimizer PEO131 will rationally allocate the charging current of each cell 133 based on parameters such as the current voltage and internal resistance of the cells 133, ensuring that the battery pack 130 as a whole can charge at the required power and that the charging process among the cells 133 remains balanced. The battery pack energy optimizer PEO131 can also process command data, detect data such as voltage, current, and temperature through the BCU (Battery Control Unit), and execute corresponding actions on the battery pack.

[0064] The CEO132 cell energy optimizer closely tracks the operating voltage of the corresponding PEO131 battery pack energy optimizer based on the received cell optimization instructions, and precisely adjusts the charging and discharging current of the corresponding cell 133 according to the instructions. Throughout the charging and discharging process, the PEO131 continuously monitors the battery pack power parameters in real time to ensure they do not exceed the allowable range of the updated battery pack status data. If within the range, the PEO131 smoothly converts the battery pack optimization instructions into multiple cell optimization instructions based on the cell status data, ensuring smooth charging and discharging operations. If the parameters exceed the range, the PEO131 feeds back the information about the excessive battery pack power parameters through the PDU120 power distribution unit. Upon receiving this information, the PCS110 power converter promptly adjusts the system's operating parameters, such as reducing charging power or adjusting the discharging strategy, to ensure the energy storage battery system remains in a safe and stable operating state. The CEO132 cell energy optimizer uses the BMU (Battery Management Unit) for cell detection and related control.

[0065] This embodiment also provides an operation control method for an energy storage battery system, used to control the operation process of the energy storage battery system in any of the above embodiments. Figure 2 This is a schematic diagram of an operation control method for an energy storage battery system according to an embodiment of the present invention. The operation control method for the energy storage battery system generally includes:

[0066] Step S211: Obtain the optimal efficiency point of the power converter PCS;

[0067] Step S212: Determine the operating voltage value of the energy optimizer PEO for each battery pack and the power index of the battery pack based on the optimal efficiency point.

[0068] Step S213: Generate battery pack optimization instructions based on the operating voltage value and battery pack power specifications;

[0069] Step S214: Distribute the battery pack optimization command to multiple battery pack energy optimizers so that the multiple battery pack energy optimizers can perform charging and discharging operations according to their respective battery pack optimization commands.

[0070] The above operating method may further include, prior to the step of obtaining the optimal efficiency point of the power converter PCS:

[0071] Step S201: After receiving the charge / discharge command during the standby phase of the energy storage battery system, collect the overall status data of the energy storage battery system.

[0072] Step S202: Send a battery pack self-test command to the battery pack energy optimizer PEO through the power distribution unit (PDU).

[0073] Step S203: Obtain the battery pack status data replied by the battery pack energy optimizer PEO in response to the battery pack self-test command;

[0074] Step S204: Update the overall status data of the energy storage battery system based on the battery pack status data;

[0075] Step S205: Perform a system self-test based on the updated overall status data of the energy storage battery system. If the self-test passes, proceed to the step of obtaining the optimal efficiency point of the power converter, i.e., proceed to step S211.

[0076] Step S206: If the self-test fails, that is, if the self-test detects an abnormality, an alarm message indicating a battery system malfunction is output.

[0077] The above operating method, based on the PCS-PDU-PEO-CEO control architecture, realizes refined control of the energy storage battery system, which can ensure that the entire energy storage battery system can operate at near the optimal efficiency of the power converter, improve the efficiency of power conversion and utilization, and reduce energy loss.

[0078] Figure 3 This is a schematic diagram of the execution flow of a power distribution unit (PDU) during the operation of an energy storage battery system according to an embodiment of the present invention. The operation process of the power distribution unit (PDU) may include:

[0079] Step S301: Start charging and discharging;

[0080] Step S302: Generate the execution command;

[0081] Step S303, system self-test;

[0082] Step S304, System status analysis;

[0083] Step S305, charging and discharging power allocation.

[0084] During operation, the PDU tracks the optimal efficiency point of the PCS under current environmental conditions and operational requirements. The PDU can utilize built-in efficiency optimization algorithms (such as efficiency prediction models based on neural networks, or efficiency curve matching algorithms fitted with a large amount of experimental data) to calculate and track the optimal efficiency point of the PCS under the current comprehensive conditions in real time. This optimal efficiency point represents the operating parameters that achieve the minimum power conversion loss and the most efficient energy utilization.

[0085] The PDU issues the optimal operating voltage value and the corresponding power requirement index of the PEO unit to the PEO. After the PDU determines the optimal efficiency point of the PCS, it will perform power and voltage allocation calculations based on the voltage, power and other parameters corresponding to that efficiency point, combined with the number of battery packs in the battery system and their current status (such as the SOC and internal resistance consistency of each battery pack).

[0086] The PEO locks the operating voltage according to the PDU command, and the CEO performs voltage tracking and always follows the PEO voltage. The CEO collects the voltage of the corresponding cell in real time and compares it with the voltage value locked by the PEO. Using its own current regulation capability, the CEO dynamically adjusts the charging and discharging current of the cell so that the terminal voltage of the cell always follows the operating voltage locked by the PEO.

[0087] The PEO unit issues power targets to the CEO based on power indicators and the cell status feedback from the battery management system. The PEO's built-in power allocation algorithm performs secondary power allocation based on the total power indicators of the battery pack and the differences in the status of each cell. For example, for cells with lower SOC and better health (low internal resistance, fewer cycle times), the algorithm will allocate relatively more charging power (in charging scenarios) to accelerate their charge replenishment, while avoiding over-allocation of power to cells with excessively high SOC or poor health to prevent overcharging, overheating, and other problems. In discharging scenarios, cells with higher SOC and stronger discharge capacity are given priority to bear more discharge power.

[0088] The CEO tracks the PEO's operating voltage and adjusts the current accordingly. Upon receiving power command instructions from the PEO, the CEO combines this with the ongoing voltage tracking task to comprehensively adjust the cell's charging and discharging current. Throughout the charging and discharging process, the CEO continuously performs closed-loop control of voltage tracking and current adjustment, performing parameter monitoring and adjustments multiple times per second (the specific frequency depends on the system's control accuracy requirements and hardware response speed). This ensures that the cells meet voltage coordination requirements and accurately execute power distribution commands, enabling all cells in the battery pack to operate efficiently, evenly, and safely during charging and discharging.

[0089] After completing charging and discharging, the PEO reports the current charging and discharging completion status of the battery pack and the final status data of the cells (such as SOC and voltage consistency after charging and discharging). The PDU then aggregates all PEO feedback information and transmits a system charging and discharging completion signal to the PCS. The PCS then stops the energy conversion operation and uploads the overall data of this charging and discharging process (such as total converted capacity, efficiency, and the participation status of each battery pack) to a higher-level control system (such as the central management system of the energy storage power station) for statistical analysis and operation and maintenance decisions. At this point, the operation process of this energy storage battery system based on optimal efficiency point tracking and hierarchical power and voltage control ends, and the system enters standby mode, waiting for the next charging and discharging command to trigger a new operating cycle.

[0090] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. An energy storage battery system, characterized in that... include: Multiple battery packs, each of which includes multiple cells connected in parallel; Multiple battery pack energy optimizers are configured one-to-one with the multiple battery packs; A power converter, electrically connected to an external electrical circuit, and configured to control the energy storage battery system to exchange electrical energy with the electrical circuit; A power distribution unit is connected to the power converter and the plurality of battery pack energy optimizers respectively, and is configured to convert the conversion instructions of the power converter into a plurality of battery pack optimization instructions, and distribute the plurality of battery pack optimization instructions to the plurality of battery pack energy optimizers so that the plurality of battery pack energy optimizers perform charging and discharging operations according to their respective battery pack optimization instructions.

2. The energy storage battery system according to claim 1, wherein, The power allocation unit is further configured to: obtain the optimal efficiency point of the power converter, determine the operating voltage value and battery pack power index of each battery pack energy optimizer based on the optimal efficiency point, and generate the battery pack optimization instruction based on the operating voltage value and the battery pack power index.

3. The energy storage battery system according to claim 2, further comprising: Multiple cell energy optimizers are configured one-to-one with each of the battery cells, and Each of the battery pack energy optimizers is also connected to the plurality of cell energy optimizers of its corresponding battery pack, and configured to convert the battery pack optimization instructions into a plurality of cell optimization instructions, and distribute the plurality of cell optimization instructions to the plurality of cell energy optimizers, so that the plurality of cell energy optimizers perform charging and discharging operations according to their respective cell optimization instructions.

4. The energy storage battery system according to claim 3, wherein Each of the battery pack energy optimizers is further configured to: lock the operating voltage of the battery pack according to the operating voltage value in the battery pack optimization instruction, and generate cell optimization instructions for each of the cell energy optimizers according to the battery pack power index in the battery pack optimization instruction.

5. The energy storage battery system according to claim 3, wherein The cell energy optimizer is also configured to track the operating voltage of the corresponding battery pack energy optimizer and adjust the charging and discharging current of the corresponding cell according to the cell optimization command.

6. The energy storage battery system according to claim 3, wherein The power converter is further configured to collect the overall status data of the energy storage battery system after receiving a charge / discharge command during the standby phase of the energy storage battery system; and to send a battery pack self-test command to the multiple battery pack energy optimizers through the power distribution unit, and to obtain the battery pack status data replied by the multiple battery pack energy optimizers in response to the battery pack self-test command. The battery pack energy optimizer is further configured to collect corresponding battery pack status data according to the battery pack self-test command, send cell self-test commands to the plurality of cell energy optimizers according to the battery pack self-test command, and obtain cell status data replied by the plurality of cell energy optimizers in response to the cell self-test command.

7. The energy storage battery system according to claim 6, wherein The battery pack energy optimizer is also configured to update the battery pack status data based on the cell status data; The power converter is also configured to update the overall status data of the energy storage battery system based on the battery pack status data.

8. The energy storage battery system according to claim 7, wherein The battery pack energy optimizer is further configured to determine whether the battery pack power index exceeds the allowable range of the updated battery pack status data. If not, the battery pack optimization instruction is converted into multiple cell optimization instructions based on the cell status data. If so, the information that the battery pack power index exceeds the limit is fed back through the power allocation unit.

9. The energy storage battery system according to claim 7, wherein The power converter is also configured to perform a system self-test based on the updated overall status data of the energy storage battery system. If the self-test passes, the converter generates the conversion command based on the overall status data of the energy storage battery system. If the self-test fails, the converter outputs an alarm message indicating an abnormality in the battery system.

10. A method for controlling the operation of an energy storage battery system, used to control the energy storage battery system according to any one of claims 1 to 9, and comprising: To obtain the optimal efficiency point of the power converter; The operating voltage value of each battery pack energy optimizer and the battery pack power index are determined based on the optimal efficiency point. Generate battery pack optimization instructions based on operating voltage values ​​and battery pack power specifications; The battery pack optimization instructions are distributed to the plurality of battery pack energy optimizers, so that the plurality of battery pack energy optimizers perform charging and discharging operations according to their respective battery pack optimization instructions.

11. The operation control method according to claim 10, wherein, The steps preceding the determination of the power converter's optimal efficiency point also include: After receiving a charge / discharge command during the standby phase of the energy storage battery system, the overall status data of the energy storage battery system is collected. The power distribution unit sends a battery pack self-test command to the battery pack energy optimizer. Obtain the battery pack status data replied by the battery pack energy optimizer in response to the battery pack self-test command; The overall status data of the energy storage battery system is updated based on the battery pack status data; The system performs a self-test based on the updated overall status data of the energy storage battery system. If the self-test passes, the system proceeds to obtain the optimal efficiency point of the power converter. If the self-test fails, an alarm message indicating an abnormality in the battery system is output.

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